The present invention relates to a roll control system for an automotive vehicle, and more specifically relates to a vehicle roll control system of the vehicle height adjustment type.
The present invention has been described in Japanese Patent Application Ser. No. Showa 61-036705 (1986), filed by an applicant the same as the entity assigned or owed duty of assignment of the present patent application; and the present patent application hereby incorporates into itself by reference the text of said Japanese Patent Application and the claims and the drawings thereof; a copy is appended to the present application.
Further, the present inventors wish hereby to attract the attention of the examining authorities to copending Patent Applications Ser. Nos. 06/921,138; 06/921,251; 06/921,450; 06/921,451; 06/921,468; 07/017,592; and 07/026,468, which may be considered to be material to the examination of the present patent application.
In general, in the operational conditions where a vehicle such as an automobile turns at a speed not less than a particular determinate turning speed value, the body of the vehicle experiences rolling, i.e. the vehicle body inclines in the radially outward direction, and this rolling results in deterioration of the drivability of the vehicle.
In order to cope with the above problem--as described in the specifications of, for example, Japanese Patent Applications Serial Nos. Sho 60-235659, Sho 60-235660, and Sho 60-235661, which are applications filed by at least one applicant the same as the entity assigned or owed duty of assignment of the present patent application, and the subject matters of some or all of which are included in the above identified Patent Applications which are copending with the present Patent Application as described above, but which it is not hereby intended to admit in any way as prior art to the present application except to the extent in any case mandated by applicable law--there have been proposed to fit to a vehicle various types of vehicle height adjustment systems comprising: a plurality of actuators which are provided for resiliently suspending the vehicle wheels from its body and are adapted to increase or decrease vehicle height at locations corresponding to the associated vehicle wheels as respective results of supplying or discharging working fluid to or from variable volume working fluid chambers of said actuators; a plurality of working fluid supplying and discharging means which are provided corresponding to the actuators and which serve to supply or discharge the working fluid to or from said actuators; a vehicle speed detecting means for detecting the road speed of the vehicle; a steering angle detecting means for detecting the steering angle of the vehicle; and a control means for controlling the working fluid supplying and discharging means by predictingly computing the roll angle of the vehicle body based upon the vehicle speed and the steering angle as sensed by these detecting means therefor, and for in accordance with this predicted roll angle reducing the rolling of the vehicle body so as thus previously and predictingly to keep said vehicle body roll within a predetermined range. Also there have been proposed to fit similar vehicle height adjustment systems, in which the differences between the actual vehicle heights at its various wheels and certain reference vehicle heights are reduced to be within predetermined ranges, again so as thereby similarly previously and positively to prevent the vehicle body from rolling.
In a vehicle equipped with such a vehicle height adjustment system as described above, however, when it should happen that the steering wheel of the vehicle is turned more quickly than in the case of normal steering action when directing the vehicle around a curve or corner--as for example is done when emergency steering action is being taken for causing said vehicle to avoid an obstacle or the like--then the speed of response of the vehicle roll control system is not always sufficiently high to definitely prevent the rolling of the vehicle body positively and precisely. In such a case, the drivability and the controllability and the comfortability of the vehicle are deteriorated, and the cornering and the road holding characteristics thereof may also suffer.